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Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement
« Last post by BrianHG on Today at 03:24:19 am »
Are you sure the source of your noise is the 74HCT4046?

What about the VCO feedback input from your 'Custom Chip'.  That loop filter with the series diode doesn't look like it can create ever guarantee a super-tight loop.  That 4.7meg as a pull-down is kinda like a weak open circuit.  I would be surprised if that circuit could even be made stable unless you have a fluke of a tuned circuit.  I would toss out that design and do things properly, then you will have no oscillator noise when using any 74HC/HCT4046 variants.
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FPGA / Re: If Lattice iCE40UltraPlus has DDR primitives like ODDR in Xilinx?
« Last post by KrudyZ on Today at 03:23:08 am »
Looking at the IO buffer diagram you can see that there are DDR structures for both inputs and outputs.
I have used these on the ICE parts and they work fine.
However, I found the PLL to be more limiting in many cases compared to let's say a MACH-XO3 device.
Also, as others have said these parts are pretty slow. Don't expect your main clock speed to be much higher than 60 MHz.
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Test Equipment / Re: SDS800X HD Wanted Features
« Last post by electronics hobbyist on Today at 03:21:20 am »
Modify the rules for adding wanted features list. "Wanted features" need the "Say Thanks  :-+" of two other people besides yourself, so you need to describe usage scenarios clearly so that you can get the approval of others. "Improvements" can lower standards.
Based on historical experience, manufacturers will not guarantee that they can add new features. Siglent is also constantly adding new functions when releasing new versions, such as the serial analysis function of sds2000x plus.
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-bugs-missing-features-feature-requests/msg5434955/#msg5434955
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Metrology / Re: ADR1001 - Ovenized Voltage Reference System
« Last post by floobydust on Today at 03:20:43 am »
This ADR1001 seems to be quite late? About 19 months.
EDN April 10, 2024 "Voltage-Reference IC with Integral Heater Offers Single PPM-Class Results" they did a blurb about it but no mention of availability.
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FPGA / Re: Gowin Simulation
« Last post by Rainwater on Today at 03:19:39 am »
Quote from: Mecanix on April 03, 2024, 03:12:21 pm
For the record. This will teach how to import the Gowin's precompiled libraries into ModelSim / QuestaSim and run simulations based on their IPcores. Tested yesterday with QuestaSim 2023 & Gowin Designer 1.9.9.01 (build71333).

https://youtu.be/2uUcYFE-3S8?t=393
Is there a kind soul that can make a transcript of what is being said? Written words are easier to translate. The translator in my phone cant keep up.
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Test Equipment / Re: SDS800X HD Wanted Features
« Last post by electronics hobbyist on Today at 03:19:32 am »
Quote from: mawyatt on April 24, 2024, 12:36:01 pm
A nice feature for all the Siglent DSOs that support Bode Plots and Math Functions would be to allow the DUT Input and Output selections to support not only Channels 1-4 but also the Math Function. With this added capability using the Bode Plots for Impedance and Admittance measurements/plots becomes more straight forward without the need for additional support equipment such as Current/Differential Probes.

For example, one could use the Math function to subtract the voltage probed across a Reference Resistor with a pair of Channels to use as the DUT current for the Bode Plot.

Best,

Added to wanted feature No.39.

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Projects, Designs, and Technical Stuff / Re: Vacuum Fluorescent Display Driver
« Last post by bostonman on Today at 03:19:25 am »
The shift register inside the HV518 chip?

I agree that the signals don't look correct, however, oddly enough, the display is almost correct (12th digit has the segment C lit and nothing else - segment C being the right vertical bottom).

Hopefully this weekend I'll have time to replace the chip.
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Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement
« Last post by moffy on Today at 03:17:06 am »
Quote from: dj_holmes on Today at 02:40:41 am
Oh wow so the normal 74HC4046 is better!?!

SN74LV4046A  Optimized Power-Supply Voltage Range From 3 V to 5.5 V
There shouldn't be much difference between the HC and HCT except logic threshold levels, the LV is a much newer technology, faster and might require you to tweak some of the timing components, I say this without having checked the datasheet. It would be fine at 5V.
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Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by AceyTech on Today at 03:14:17 am »
Quote from: mrisco on Yesterday at 11:27:20 pm
Yes, it is real   ;D

Nicely done.  Very sexy!  8)

BTW: @AndyBig @Shapirus and @Randy222 were all experimenting with the UI elements a short while ago.  Are you continuing with their work or doing something different?
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Beginners / Re: Put LC filter before or after LDO?
« Last post by antercreeper on Today at 03:12:18 am »
I have tested(filter in front of the LDO)
And result is I need to add more output capacitors maybe 10uF or more, because the load generate ripples on the output(about several millvolts). while the load is shut down and ripples are gone. (In fact I think the biggest reason is MLCC's capacitance degraded by DC bias  :-DD I forgot this and mess all things)
maybe later I can change the input filter capacitors from MLCC to tantalum one, but by now haven't observed any problems.
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